NephrolithiasisHETEROCYPNCT07201701
Is CYP24A1 Heterozygosity a Risk Factor for Nephrolithiasis?
An observational study of Nephrolithiasis, run by Hospices Civils de Lyon at 2 sites in France.
Trial summary
Biallelic loss-of-function variants in CYP24A1 have been identified as a common genetic cause of autosomal recessive hypercalcemia (ARH, ORPHA 300547, 1 in 80,000 live births), characterized by low PTH (parathyroid hormone) levels, a high 25-OH D/24,25-(OH)₂D ratio, and susceptibility to vitamin D intoxication. Read more about this study
- Who is it for?
- Ages 2 to 90 years
- Conditions the study is for
- Nephrolithiasis
- What is being tested?
- Supplementary blood samples for PBMC analysis at V2
- How many people
- 45 participants
- Where
- 2 sitesFrance
- Study dates
- 1 Dec 2025to 1 Apr 2028
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 2 to 90 years
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: The study focuses on patients who are CYP24A1 heterozygous, CYP24A1 homozygous, or compound heterozygous.
Who may be able to join
- Group 1: Heterozygous Patients
- Aged between 2 and 90 years
- Weight > 12 kg
- Carriers of a heterozygous CYP24A1 mutation
- With or without symptoms: history of nephrocalcinosis or kidney stones
- Group 2: Homozygous / Compound Heterozygous Patients
Show all 10Show fewer
- Aged between 2 and 90 years
- Weight > 12 kg
- Carriers of a homozygous or compound heterozygous CYP24A1 mutation
- With or without symptoms: history of nephrocalcinosis or kidney stones
Who cannot join
- Individuals unable to collect 24-hour urine
- Individuals unable to be available for a full day in a day hospital (HDJ)
- Pregnant, postpartum, or breastfeeding women
- Individuals deprived of liberty by judicial or administrative decision
- Individuals receiving psychiatric care
- Individuals admitted to a healthcare or social institution for reasons other than participation in research
- Adults under legal protection (guardianship or trusteeship)
- Individuals not affiliated with a social security system or not benefiting from an equivalent scheme
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
France2 sites
Hôpital Femme Mère Enfant
Bron
Justine Pr BACCHETTA, 0033427856178, Justine.bacchetta@chu-lyon.fr
Hôpital Edouard Herriot
Lyon
Sandrine Pr LEMOINE, 0033472110252, sandrine.lemoine01@chu-lyon.fr
About this study
Biallelic loss-of-function variants in CYP24A1 have been identified as a common genetic cause of autosomal recessive hypercalcemia (ARH, ORPHA 300547, 1 in 80,000 live births), characterized by low PTH (parathyroid hormone) levels, a high 25-OH D/24,25-(OH)₂D ratio, and susceptibility to vitamin D intoxication.
In humans, heterozygous pathogenic variants in CYP24A1 have been proposed both as responsible for an autosomal dominant disorder and as a risk factor for nephrolithiasis, but the rarity and heterogeneity of human data prevent a definitive answer to this crucial question.
Read more
Nephrolithiasis is a complex disease in which nutritional factors - particularly sodium and protein intake (leading to hypercalciuria) - play a key role. It also has a heritability of 50%, suggesting the involvement of many genetic susceptibility factors, as well as monogenic forms (mainly autosomal recessive, but also dominant or X-linked), which have been identified in 10-20% of patients.
The increasing prevalence of nephrolithiasis, affecting approximately 10% of the general population over a lifetime, has a significant financial impact on healthcare systems and imposes a major burden of morbidity, justifying further investigation into the genetic underpinnings of nephrolithiasis.
The goal of the HeteroCYP project is to improve understanding of the phenotypes associated with heterozygous, compound heterozygous, and homozygous variants of CYP24A1 by comparing clinical and biological outcomes in patients according to their mutation type
- Conditions
- Nephrolithiasis
- Being tested
- Supplementary blood samples for PBMC analysis at V2
- Keywords
- CYP24A1 heterozygous, Nephrolithiasis, CYP24A1 homozygous, and compound heterozygous, Nephrocalcinosis
- Medical subject headings
- Nephrolithiasis, Nephrocalcinosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Supplementary blood samples for PBMC analysis at V2Biological
Supplementary blood (serum and plasma) and urines samples for bio collection at V3
| Study group | Role | What they receive |
|---|---|---|
| Patients carriers of a heterozygous CYP2A1 mutation | Patients carriers of a heterozygous CYP2A1 mutation with or without symptoms: history of nephrocalcinosis or nephrolithiasis Receives: Biological: Supplementary blood samples for PBMC analysis at V2 | |
| Patients carriers of homozygous, and compound heterozygous CYP2A1 mutation | Patients carriers of homozygous, and compound heterozygous CYP2A1 mutation with or without symptoms: history of nephrocalcinosis or nephrolithiasis Receives: Biological: Supplementary blood samples for PBMC analysis at V2 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Prevalence of nephrolithiasis in patients who are CYP24A1 heterozygous and homozygous (or compound heterozygous)
Prevalence of nephrolithiasis (based on imaging) in patients who are CYP24A1
Measured: Visit 2 (at least 24 hours after baseline)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Oct 2025
- Study start1 Dec 2025 (estimated)
- Primary completion1 Oct 2026 (estimated)
- Study completion1 Apr 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for NephrolithiasisStudies of the same condition, open and under way.
- More trials run by Hospices Civils de LyonThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 45 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Hospices Civils de Lyon
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Justine Pr BACCHETTA, Principal investigator, Hospices Civils de Lyon
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07201701
- Sponsor's protocol ID
- 69HCL25_0507
- Other IDs
- 2025-A01749-40
- Acronym
- HETEROCYP
- Status last verified
- Nov 2025
- First submitted
- 22 Sep 2025
- Last updated
- 2 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 2 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Is CYP24A1 Heterozygosity a Risk Factor for Nephrolithiasis?
- ClinicalTrials.gov ID
- NCT07201701
- Acronym / sponsor ID
- HETEROCYP / 69HCL25_0507
- Conditions
- Nephrolithiasis
- Keywords
- CYP24A1 heterozygous, Nephrolithiasis, CYP24A1 homozygous, and compound heterozygous, Nephrocalcinosis
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 45 participants (estimated)
- Lead sponsor
- Hospices Civils de LyonUniversity, hospital or other
- Study start
- 1 Dec 2025 (estimated)
- Primary completion
- 1 Oct 2026 (estimated)
- Study completion
- 1 Apr 2028 (estimated)
- First posted
- 1 Oct 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Biallelic loss-of-function variants in CYP24A1 have been identified as a common genetic cause of autosomal recessive hypercalcemia (ARH, ORPHA 300547, 1 in 80,000 live births), characterized by low PTH (parathyroid hormone) levels, a high 25-OH D/24,25-(OH)₂D ratio, and susceptibility to vitamin D intoxication.
In humans, heterozygous pathogenic variants in CYP24A1 have been proposed both as responsible for an autosomal dominant disorder and as a risk factor for nephrolithiasis, but the rarity and heterogeneity of human data prevent a definitive answer to this crucial question.
Nephrolithiasis is a complex disease in which nutritional factors - particularly sodium and protein intake (leading to hypercalciuria) - play a key role. It also has a heritability of 50%, suggesting the involvement of many genetic susceptibility factors, as well as monogenic forms (mainly autosomal recessive, but also dominant or X-linked), which have been identified in 10-20% of patients.
The increasing prevalence of nephrolithiasis, affecting approximately 10% of the general population over a lifetime, has a significant financial impact on healthcare systems and imposes a major burden of morbidity, justifying further investigation into the genetic underpinnings of nephrolithiasis.
The goal of the HeteroCYP project is to improve understanding of the phenotypes associated with heterozygous, compound heterozygous, and homozygous variants of CYP24A1 by comparing clinical and biological outcomes in patients according to their mutation type
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Patients carriers of a heterozygous CYP2A1 mutation | – | Biological: Supplementary blood samples for PBMC analysis at V2Patients carriers of a heterozygous CYP2A1 mutation with or without symptoms: history of nephrocalcinosis or nephrolithiasis |
| Patients carriers of homozygous, and compound heterozygous CYP2A1 mutation | – | Biological: Supplementary blood samples for PBMC analysis at V2Patients carriers of homozygous, and compound heterozygous CYP2A1 mutation with or without symptoms: history of nephrocalcinosis or nephrolithiasis |
Who may qualify
- Ages
- 2 to 90 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- The study focuses on patients who are CYP24A1 heterozygous, CYP24A1 homozygous, or compound heterozygous.
Key inclusion criteria (10 listed)
- Group 1: Heterozygous Patients
- Aged between 2 and 90 years
- Weight > 12 kg
- Carriers of a heterozygous CYP24A1 mutation
- With or without symptoms: history of nephrocalcinosis or kidney stones
Key exclusion criteria (8 listed)
- Individuals unable to collect 24-hour urine
- Individuals unable to be available for a full day in a day hospital (HDJ)
- Pregnant, postpartum, or breastfeeding women
- Individuals deprived of liberty by judicial or administrative decision
- Individuals receiving psychiatric care
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Supplementary blood samples for PBMC analysis at V2Supplementary blood (serum and plasma) and urines samples for bio collection at V3 | Biological | Patients carriers of a heterozygous CYP2A1 mutation, Patients carriers of homozygous, and compound heterozygous CYP2A1 mutation |
Primary outcome
Prevalence of nephrolithiasis in patients who are CYP24A1 heterozygous and homozygous (or compound heterozygous)
Time frame: Visit 2 (at least 24 hours after baseline)
Prevalence of nephrolithiasis (based on imaging) in patients who are CYP24A1
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Dec 2025.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Justine Pr BACCHETTA principal investigator
Hospices Civils de Lyon
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Nephrolithiasis, run by Hospices Civils de Lyon at 2 sites in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 2 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Justine Pr BACCHETTA (0033427856178, Justine.bacchetta@chu-lyon.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Prevalence of nephrolithiasis in patients who are CYP24A1 heterozygous and homozygous (or compound heterozygous) (time frame: Visit 2 (at least 24 hours after baseline)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Dec 2025.